Learn Danish: Opskriften er meget enkel. - The recipe is very simple.

In Danish, nem generally means easy (the opposite of difficult), focusing on the effort required. Enkel means simple (the opposite of complex), focusing on having few parts or straightforward steps. A recipe can be enkel (few ingredients) but still not necessarily nem to execute, although the two concepts often overlap in cooking.

Enkel ends in -el. How does this affect its ending if we were talking about multiple recipes?

Adjectives ending in -el, -en, or -er drop the final e in the root when they take the plural or definite -e ending. So if the subject were plural, you would say opskrifterne er meget enkle (not enkele).

Since opskrift means recipe, can I also use it for a medical prescription?

No, this is a common false friend. For a medical prescription, Danish uses the word recept (which looks like recipe!). Opskrift is used for food or crafting instructions, as well as metaphorically, such as en opskrift på en katastrofe (a recipe for disaster).